I often see questions in the close queue that people have VTC'ed or flagged as "unclear what you're asking" without leaving a comment. I've adopted my own policy about this, and I'd like to see more people do the same, to help new users, non-native speakers, and others who have trouble writing clear questions on the site.
The policy is this: I won't VTC a question as "unclear what you're asking" without leaving a comment asking the user to clarify or add more information.
We get a lot of troubleshooting questions on this site, and often they don't contain all the necessary information: they're about manufacturer apps but the questioner doesn't say what phone he has; they're about behaviour that's different in different Android versions, but the questioner doesn't say which version he's using. In cases where there's so much missing information that nobody could reasonably hope to answer the question, because even if they've seen exactly the same problem before, they wouldn't recognise it from the question, then voting to close as "unclear" is entirely appropriate. This adds a note to the question asking for more information.
But in this case, it's also unclear what we're asking. "Please add further details to your question... but we're not going to tell you what details." This doesn't help the questioner at all. If he knew he needed to say what phone he has, or which particular step of a process went wrong, or what the actual behaviour was (instead of "doesn't work"), then he'd have included that information in the first place. We can only arrive at a useful question by telling the questioner what he needs to do.
The same applies to other kinds of "unclear what you're asking". If it's unclear because it's badly written or the English doesn't make sense, it's courteous to explain what the problem is, as precisely as possible. If it's unclear because there's no question asked, it may be a simple oversight, or it may be that it's a new user who doesn't understand the Q&A format. Either way, the only way to end up with an answerable question is to say what's wrong, and what the questioner needs to do to fix it. The default "unclear what you're asking" banner is generic and vague, and doesn't tell the questioner what's wrong with his question in particular.
For this reason, I'm asking for everyone on the site to post a comment before VTC'ing a question as "unclear what you're asking". Out of all the close reasons, it's the least self-explanatory. If we do this well, and the questioner is eagerly looking out for responses, it may be that the question can be fixed before it is even closed, which is ideal.